An airbag device of an automobile and the like is configured such that an inflator is operated at the time of collision and the like to generate a gas, so that an airbag is rapidly inflated by the gas and restrains an occupant. For example, the airbag device is mainly configured from an airbag, a retainer mounted with the airbag, an inflator for supplying an inflation gas to the airbag, a pressing ring for mounting the airbag in the retainer, and a module cover which covers the airbag folded at the normal time (when an emergency such as a vehicle collision does not occur) (for example, see Patent Literature 1).
An opening for mounting the inflator is provided in the vicinity of the center of the retainer. A plurality of bolt insertion holes are provided at the same interval therearound. The inflator is fitted into the inflator opening, and a flange which projects sideward from the side circumferential surface thereof abuts on the peripheral edge of the inflator opening of the retainer. The flange of the inflator is provided with bolt insertion holes which are overlapped coaxially with the bolt insertion holes of the retainer.
A peripheral edge of a gas introduction opening of the airbag is superposed in the peripheral edge of the inflator opening of the retainer, and is nipped between a pressing ring and the peripheral edge of the inflator opening of the retainer. The bolt insertion holes which are overlapped coaxially with the bolt insertion holes of the retainer are also provided around the gas introduction opening of the airbag.
A plurality of stud bolts protrude at the same interval in the pressing ring. The stud bolts penetrate respectively the bolt insertion holes which are overlapped coaxially with the airbag, the retainer, and the flange of the inflator. When the nuts are fastened into the stud bolts respectively, the pressing ring, the airbag, and the inflator are connected and fixed in the retainer.
An airbag device is known which holds an inflator without a flange for mounting and fixing (for example, see Patent Literature 2). The airbag device includes the inflator, a retainer, an airbag, and a bag ring for mounting a peripheral edge of an opening of the airbag in the retainer. The bag ring includes a cylindrical portion which supports the end surface of the inflator in an axial direction, and a flange portion which extends from the cylindrical portion in a diameter direction.
A through hole which penetrates in the axial direction is provided in the flange portion of the bag ring, the airbag, and the retainer. By fastening the bolt inserted into the through hole, the bag ring, the airbag, and the retainer are fixedly mounted integrally with each other while holding the inflator.
In the above-described conventional airbag device, it is inevitable that a process is performed which inserts the bolt into the through hole provided in the flange of the inflator or the flange portion of the bag ring, and fastens the nut therein when the inflator is fixedly mounted. The process makes an assembly operation of the airbag device complicated, which causes cost to increase.